In recent years, with increasingly higher functionality of information apparatus, there is a demand for higher mounting density and higher performance of semiconductor devices mounted on such information apparatus. One of the semiconductor device mounting techniques that address such a demand is a mounting structure using a buildup substrate.
In the semiconductor device mounting structure using a buildup substrate, the buildup substrate is a rigid substrate including a core layer of glass epoxy resin or the like and wiring layers formed on the upper and lower surfaces of the core layer, for example. The upper and lower wiring layers are connected to each other by vias extending through the core layer. A plurality of semiconductor elements such as a CPU and a memory element are mounted on the buildup substrate, forming a semiconductor device. This semiconductor device is mounted above a system board built in a server, supercomputer, or other information apparatus via a plurality of mounting terminals formed on the rear surface of the buildup substrate.
To reduce the inductance component that increases high-frequency noise generated by the semiconductor device, there is a mounting structure in which a plurality of chip components such as capacitors that remove the high-frequency noise are mounted on the rear surface of the system board directly below the semiconductor device. The closer to the semiconductor device the chip components are, the more effectively the high-frequency noise is removed. There is accordingly another mounting structure in which an opening is provided in the system board in an area above which the semiconductor device is mounted and a plurality of chip components such as capacitors are provided inside the opening on the rear surface of the buildup substrate of the semiconductor device.
The following is reference documents:    [Document 1] Japanese Laid-open Patent Publication No. 2008-227310.